Update pt.json

[Tangara-cayana]

• aligned with the em.json file.
• added about 60 lines.
• some syntax changes.
• punctual corrections.
• some terms kept in eng due to being incorporated into the language

[xaur]

I asked in the #translators room if anyone can review this but no response so far.

An alternative approach we can take is "lazy consensus", that is don't block the merge on review and fix translations bugs if anyone reports them. My reasoning is that, a) we don't know when a reviewer for pt-BR shows up (it might take a while), b) when contribs are merged it motivates to do more (and vice versa), c) seeing a translation on the site may actually provoke someone to review or submit more fixes.

[jholdstock]

@victorgcramos it looks like @Tangara-cayana might not come back. Do you think you could finish this translation and open a fresh PR?

[dajohi]

Applied in #1160